For example in the field of disaster prevention, personnel must be equipped with certain devices to fulfill their responsibilities. The verification of the equipment scope is frequently difficult and can often not be reliably performed, especially when staff is pressed for time. It may also happen that equipment is lost without the staff being aware of it and that the loss goes initially undetected. The undetected loss of objects from the immediate vicinity of a person, for example the loss of valuables through inattention or theft, is a common problem in every-day life as well.